On Conditionals provides the first major cross-disciplinary account of conditional (if-then) constructions. Conditional sentences directly reflect the language user's ability to reason about alternatives, uncertainties, and unrealised contingencies. An understanding of the conceptual and behavioural organisation involved in the construction and interpretation of these kinds of sentences therefore provides fundamental insights into the inferential strategies and the cognitive and linguistic processes of human beings. The present volume brings together studies from several perspectives - philosophical, linguistic and psychological - and aims to emphasise the intrinsic connections between the issues to be addressed and to point to new directions for interdisciplinary work.